1. Field of the Invention
This invention relates to a method and an apparatus for loading raw material into a quartz crucible of silicon single-crystal manufacturing devices in which the CZ method is employed.
2. Description of Prior Art
The substrates of semiconductor components are mainly made of high-purity silicon single crystal that is conventionally produced by the CZ method. In the CZ method, polycrystalline silicon lumps are fed into a quartz crucible of a single-crystal manufacturing device. Then, the quartz crucible is heated by heaters disposed therearound to melt the polycrystalline silicon lumps, after which a seed crystal installed on a seed chuck is dipped into the melted liquid. After that, the seed chuck and the quartz crucible are respectively driven to rotate in opposite or identical directions, and at the same time the seed chuck is lifted to grow a single-crystal silicon ingot of predetermined diameter and length. Furthermore, means for providing grain-shaped silicon materials are disclosed in, for example, Japanese Patent Publication Nos. 60-33210, 63-287565 and 9-208368.
Before manufacturing silicon single crystal by the CZ method, a preset amount of polycrystalline silicon has to be fed into the quartz crucible. Polycrystalline silicon is very hard and in the shape of lumps (Polycrystalline silicon chunk/Polycrystalline silicon nugget) having sharp protrusions. The quartz crucible is brittle; therefore polycrystalline silicon lumps, which is of 20-110 mm in size and reaches an amount of 90% in total volume, has to be fed into the quartz crucible one by one and by hands. Accordingly, loading polycrystalline silicon is a very simple operation yet a time-consumption procedure. Especially, following the enlargement of silicon single crystals, loading polycrystalline silicon into the quartz crucible is much more time-consumption.